Novak and Nadal are still the beneficiaries of the state of the field.
In 2018 the 'lost generation' (so called) was already lost - wasn't Berdych's last good match against Fed at AO 2018? Kei can still go part of the way but that's all. Cilic really went into decline at his inexplicable Wimbledon loss and has never recovered. Raonic - permanent resident in a hospital somewhere.
In 2018 the 'next gen' (so called) was in its infancy, Zverev above the rest, but already disappointing, Them ... well ... and anyway he's stuck in the middle like Grigor.
Therefore Novak and Nadal had little opposition on way to semis. Federer was more or less the Wimbledon favourite but displayed the vulnerability that's always being cited about older players and turned out to have been injured (???).
THIS YEAR Novak and Nadal continue to be the beneficiaries of the state of the field.
Most of 'lost gen' more lost than ever. 'Next gen' still not up to it.
But things have changed slightly. Stan and Delpo making a bit of a come back, more dangerous than last year, though perhaps not dangerous enough. Federer playing better than last year and clay practice helps him (I think).
'Nest gen' are improving however much posts on this site sneer. Not improving enough but at least now dominate early rounds of big tournaments. Late arrivals like Struff and the Serbs doing a bit of damage.
I believe Nole the Robot likely to win FO and Wimbledon. This is horrible. But I find a crumb of comfort in believing that in 2020 Youth will finally stand up to be counted (just as just possibly the youth of Britain will finally get rid of the Brexiteers - I regard Novak as the tennis equivalent of Brexit, by the way, destroying tennis just like Brexit is destroying UK.)